Some SRX3xx platforms may trigger a reboot under specific conditions involving LTE configuration changes.

This issue may occur when:

• The device is an SRX3xx series platform, and
• The LTE configuration is deleted and then added back

The reboot is accompanied by a panic assertion and may also generate a VM crash log.

This behavior is extremely rare, and the device usually recovers automatically after reboot.

• Unexpected reboot immediately after LTE configuration changes
• High-availability setups may report temporary failover behavior
• Reboot reason shows: Last reboot reason panic:Assertion jtimer_initialized_internal(jt) (file ../../../../../../../../src/junos/bsd/sys/ker

Logs to be collected:

start shell user root

% srxsmec -d exception

Additionally, confirm if core files exist under: show system core-dumps no-forwarding

• Please configure the following commands on the SRX to enable the required daemon traces:

set system processes wireless-wan-service traceoptions file wwand.log

set system processes wireless-wan-service traceoptions file size 1m

set system processes wireless-wan-service traceoptions file files 10

set system processes wireless-wan-service traceoptions flag all

set system processes dialer-services traceoptions file dood.log

set system processes dialer-services traceoptions file size 1m

set system processes dialer-services traceoptions file files 10

set system processes dialer-services traceoptions flag all

set system syslog file messages any any

• The logs will be stored in /var/log/ by the name specified above.
• Collect and review the contents of the /var/log/ directory the next time the vmcore is observed.

** A fix is available in Junos OS 26.x.

• The issue was caused by the modem interface driver accessing an incorrect internal index. When the modem disconnects—particularly in HA setups—certain internal values can become stale.
• Accessing these stale values can trigger the assertion that leads to a reboot.
• The fix ensures the driver accesses the correct, valid index during modem disconnect events.